cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A140547 Primes p such that neither p - 10 nor p + 10 is prime.

Original entry on oeis.org

2, 5, 11, 59, 67, 101, 109, 131, 151, 179, 193, 197, 199, 211, 227, 257, 263, 269, 277, 311, 313, 331, 353, 367, 397, 401, 461, 463, 479, 487, 491, 503, 521, 523, 541, 563, 569, 571, 593, 599, 601, 613, 619, 647, 659, 661, 677, 727, 739, 757, 769, 773, 809
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Jun 30 2008, Nov 07 2009

Keywords

Crossrefs

Cf. A023203, A092146.

Programs

  • Mathematica
    Select[Prime[Range[140]],!PrimeQ[#+10]&&(!PrimeQ[#-10]||#<10)&] (* James C. McMahon, Jul 12 2025 *)

Extensions

Edited by Charles R Greathouse IV, Mar 25 2010

A271549 Primes p such that p+10^2, p+10^3, p+10^5, p+10^7, p+10^11, p+10^13 and p+10^17 are all prime.

Original entry on oeis.org

1399, 2157763, 13034041, 38208649, 38502313, 41518651, 42745111, 48154147, 49435063, 53872447, 58981513, 75194563, 83037247, 86139409, 101533963, 106287019, 140778403, 144593431, 155554237, 166083133, 166650193, 189371671, 199865893, 201738379, 224472877, 240133753, 271331773
Offset: 1

Views

Author

Emre APARI, Apr 10 2016

Keywords

Comments

The exponents of 10 are all prime (2,3,5,7,11,13,17).

Examples

			p = 1399:
p+10^2  = 1499 (is prime).
p+10^3  = 2399 (is prime).
p+10^5  = 101399 (is prime).
p+10^7  = 10001399 (is prime).
p+10^11 = 100000001399 (is prime).
p+10^13 = 10000000001399 (is prime).
p+10^17 = 100000000000001399 (is prime).

Crossrefs

Cf. A000040, A002385, A015916, A023203, A271575.

Programs

  • Mathematica
    Select[Prime[Range[10^9]], PrimeQ[# + 10^2] && PrimeQ[# + 10^3] && PrimeQ[# + 10^5] &&  PrimeQ[# + 10^7] && PrimeQ[# + 10^11] &&  PrimeQ[# + 10^13] && PrimeQ[# + 10^17] &] (* Robert Price, Apr 10 2016 *)
  • PARI
    lista(nn) = forprime(p=2, nn, if (isprime(p+10^2) && isprime(p+10^3) && isprime(p+10^5) && isprime(p+10^7) && isprime(p+10^11) && isprime(p+10^13) && isprime(p+10^17), print1(p, ", "))); \\ Altug Alkan, Apr 10 2016

Extensions

More terms from Altug Alkan, Apr 10 2016

A309392 Square array read by downward antidiagonals: A(n, k) is the k-th prime p such that p + 2*n is also prime, or 0 if that prime does not exist.

Original entry on oeis.org

3, 5, 3, 11, 7, 5, 17, 13, 7, 3, 29, 19, 11, 5, 3, 41, 37, 13, 11, 7, 5, 59, 43, 17, 23, 13, 7, 3, 71, 67, 23, 29, 19, 11, 5, 3, 101, 79, 31, 53, 31, 17, 17, 7, 5, 107, 97, 37, 59, 37, 19, 23, 13, 11, 3, 137, 103, 41, 71, 43, 29, 29, 31, 13, 11, 7, 149, 109
Offset: 1

Views

Author

Felix Fröhlich, Jul 28 2019

Keywords

Comments

The same as A231608 except that A231608 gives the upward antidiagonals of the array, while this sequence gives the downward antidiagonals.
Conjecture: All values are nonzero, i.e., for any even integer e there are infinitely many primes p such that p + e is also prime.
The conjecture is true if Polignac's conjecture is true.

Examples

			The array starts as follows:
3,  5, 11, 17, 29, 41, 59,  71, 101, 107, 137, 149, 179, 191
3,  7, 13, 19, 37, 43, 67,  79,  97, 103, 109, 127, 163, 193
5,  7, 11, 13, 17, 23, 31,  37,  41,  47,  53,  61,  67,  73
3,  5, 11, 23, 29, 53, 59,  71,  89, 101, 131, 149, 173, 191
3,  7, 13, 19, 31, 37, 43,  61,  73,  79,  97, 103, 127, 139
5,  7, 11, 17, 19, 29, 31,  41,  47,  59,  61,  67,  71,  89
3,  5, 17, 23, 29, 47, 53,  59,  83,  89, 113, 137, 149, 167
3,  7, 13, 31, 37, 43, 67,  73,  97, 151, 157, 163, 181, 211
5, 11, 13, 19, 23, 29, 41,  43,  53,  61,  71,  79,  83,  89
3, 11, 17, 23, 41, 47, 53,  59,  83,  89, 107, 131, 137, 173
7, 19, 31, 37, 61, 67, 79, 109, 127, 151, 157, 211, 229, 241
5,  7, 13, 17, 19, 23, 29,  37,  43,  47,  59,  73,  79,  83

Links

Crossrefs

Cf. A231608.
Cf. A001359 (row 1), A023200 (row 2), A023201 (row 3), A023202 (row 4), A023203 (row 5), A046133 (row 6), A153417 (row 7), A049488 (row 8), A153418 (row 9), A153419 (row 10), A242476 (row 11), A033560 (row 12), A252089 (row 13), A252090 (row 14), A049481 (row 15), A049489 (row 16), A252091 (row 17), A156104 (row 18), A271347 (row 19), A271981 (row 20), A271982 (row 21), A272176 (row 22), A062284 (row 25), A049490 (row 32), A020483 (column 1).

Programs

  • PARI
    row(n, terms) = my(i=0); forprime(p=1, , if(i>=terms, break); if(ispseudoprime(p+2*n), print1(p, ", "); i++))
array(rows, cols) = for(x=1, rows, row(x, cols); print(""))
array(12, 14) \\ Print initial 12 rows and 14 columns of the array
Previous Showing 31-33 of 33 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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